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Is the Quadra 610 Quaddoubler supposed to work in an LC475?
Posted by: Bolle on 2026-03-13 08:01:04 I received the card yesterday and dived right into it. Mapped out the schematics and found a broken connection on a data line that should obviously have been connected. After looking around I quickly found a suspiciously looking trace. I have yet to repair and test the card but I'm certain it's going to work afterwards. It looks like one pin got lost while moving the card around between Macs so I have to replace that one too. What kept me distracted from repairing the card in the first place was drawing coloured lines 😅 24 hour turnaround reverse engineering right there. The GAL20RA10 has also been cracked but not yet verified because I don't have any of that type around. Looks like sourcing them is not going to be too easy. Will keep everyone updated.
Posted by: Bolle on 2026-03-13 08:55:56 One small patch wire later and swapped the broken pin with another one that's unused... And it's fixed. To totally not answer the initial question if the Q610 variant would work in the LC475 or not I gave it a quick spin in my Q700 because it has been sitting in my office anyways. While it blocks the Nubus slots it just humming along nicely.
Posted by: Bolle on 2026-05-07 09:08:50 After being busy with real world tasks I finally had some time to troubleshoot why my clone wouldn't work initially... Turned out the MC88916 I took from a roll of NOS chips that all were fine so far was actually bad. Schematics and board were spot on first try. 🙂
Posted by: croissantking on 2026-05-07 09:57:16 The only difference is that the memory performance is a tiny bit better on the 605 Really? So does an LC475 tighten RAM timings when the Q605 jumper is set?
Posted by: Phipli on 2026-05-07 10:05:41 Really? So does an LC475 tighten RAM timings when the Q605 jumper is set? I believe so - it doesn't make much difference, and to be honest, tighter timings mean less overclock... Also if you are running my control strip it overwrites the timings anyway.
Posted by: Phipli on 2026-05-07 10:09:49 After being busy with real world tasks I finally had some time to troubleshoot why my clone wouldn't work initially... Turned out the MC88916 I took from a roll of NOS chips that all were fine so far was actually bad. View attachment 98569 Schematics and board were spot on first try. 🙂 Nice work Bolle 🙂 So what happens if you plug a quad doubler into a quad doubler? Do you get a Hex Doubler?
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